What is a side return extension?

A side return extension fills the narrow passage that runs alongside the back addition of many Victorian and Edwardian terraced houses. It widens a galley kitchen into a proper kitchen-diner, usually with a sloping glazed roof to keep the room bright.
How much does a side return extension cost in Cumbernauld?
In Cumbernauld, a side return extension typically costs £2,250–£3,200 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £27,000–£38,500. Building costs in Scotland are close to the UK average, so the figures for Cumbernauld are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £18,000–£25,500 |
| Typical project (12 m²) | £27,000–£38,500 |
| Larger project (17 m²) | £38,000–£54,500 |
| Rate per m² | £2,250–£3,200 |
What moves the price most:
- Agreements with neighbours on shared walls
- Steel beams and propping of the back addition
- Moving drains and soil stacks
- Access through the house for materials
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a side return extension in Cumbernauld?
Here is how the rules work for a side return extension in Scotland. In Scotland a single-storey infill beside a back addition can be permitted development within the height and boundary limits, but not in a conservation area. A building warrant is needed before work starts.
Scotland has no Party Wall Act. Work on shared walls is governed by your title deeds, the Tenements (Scotland) Act 2004 for flats, and common law, so we agree arrangements with neighbours in writing before work starts.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a side return extension:
- Written agreement with neighbours on shared walls
- Drawings and planning or permitted development check
- Foundations and drainage, including any build-over agreement
- Floor levelling, heating and electrics
- Building control sign-off
- Steel beams to remove the side wall
How long does it take?
Allow 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Cumbernauld
Scotland’s housing ranges from sandstone tenements and villas to post-war and modern estates, and the building warrant system shapes how projects are planned.
We work across Cumbernauld and neighbouring areas such as Airdrie, Coatbridge and Kirkintilloch. Postcodes we cover in Cumbernauld include G67.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about side return extensions in Cumbernauld
How much does a side return extension cost in Cumbernauld?
In Cumbernauld, a side return extension typically costs £2,250–£3,200 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £27,000–£38,500. Your fixed price depends on the survey and drawings.
Can I stay in the house?
Usually, though the kitchen will be out of action for several weeks. We plan a temporary kitchen area where possible.
Do I need planning permission for a side return extension in Cumbernauld?
In Scotland a single-storey infill beside a back addition can be permitted development within the height and boundary limits, but not in a conservation area. A building warrant is needed before work starts.
How do you get materials in?
Mid-terrace houses often have no rear access, so materials come through the house. We protect floors and plan deliveries carefully.
How long does a side return extension take in Cumbernauld?
Typically 10 to 14 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
Is a glass roof too hot or cold?
Modern solar-control double or triple glazing reduces glare and heat loss. Building regulations also limit how much glazing you can have unless the design shows it performs well enough.
